P_is_for_Paul

Easy enough question, one ive wondered for ages, ive got a mini cooper s, can you put a dump valve on them? Ive heard both stories, that you can and you cant so was wondering if anyone actually knew the truth? Just wondered cos i saw this Clio V6 supercharged and it dumps!!

http://www.youtube.com/watch?v=zZvcQ27aWmw

ECU Monitor Enthusiast

iTrader: (1)

Yes you can. Exactly the same method as per turbo car.

Trouble is, super chargers boost levels rarely rise above 1 bar of boost
so generally a dump valve isnt needed as also, the charger is engine
driven so is less likely to slow down with reverse air flow.

Pointless IMO unless really wild set up - Unless you just want the sound

P_is_for_Paul

Yeah its all about the noise LOL

Im tryin to pretend ive still got my RST, i miss it

big_wig_074

surely itll just keep dumping or something?as the supercharger keeps spinning?what a waste of time!weird.i thought you needed an electrically operated one too?

Stavros

Only gaylord supercharged cars run low boost like that.

Ive seen CooperS's on stock chargers running 24psi, never mind other stuff.

Charger will never slow down due to reverse airflow unless the belt slips/snaps unless we talking about homo centrefugual chargers, and the CooperS has a "real" one.

Infact there will be no reverse airflow, on a proper charger as they sealed units, positive displacment devices, when the throttle shuts (if the throttle is AFTER the charger, i think it is on a Mini), unless there a bypass or vent that opens every time the throttle shuts there will be a massive boost spike before the turbo, not any reverse flow.

Minis have bypasses as standard, IIRC its a small throttle type flap opened by a wastegate actuator looking thing.

Dumpvalves are homo, if you want good noise, just fit an induction kit and a smaller supercharger pulley to speed up the charger rpm so you get a much louder whine

P_is_for_Paul

Alta induction kits comin on monday from lohen & will hopefully have smaller pulley & bluefin within the next 2 month, but id still like a dump valve!!!

paul16v

I used to have a golf G60 and on the bottom of the throttle body was another butterfly when the throttle was fully shut it was open and this just redirected the air back into the charger so it basically just recirculated the air untill you opened the throttle again, alot of ppl with them used to blank the side of the charger off with the boost return pipe on or fit twin inlet kits to them so the charger was sucking from both sides and just let the throttle body vent to atmosphere thus making it in effect dump off was supposed to cool inlet temps down aswell never bothered doing it with mine.

neilm

My 1960's Shorrock has a 'Pop Off Valve' to release pressure not when you change gear like a Chump Valve but to release pressure if the level of boost gets too high, for whatever reason, be it the engine over revving etc

StationMiek

Isn't a supercharger constantly boosting? I remember the G60 had a valve that was open most of the time which gave it that hissing sound character.

Do we put the dump valve on the pipe after the internal valve?

P_is_for_Paul

Just put my induction kit on monday there - HOLY SHIT. The noise is incredible!! Sounds like a bloody x-wing from star wars! Only problem is, cant keep my right foot off the pedal cos i love the noise

Hooligan

I love the really loud supercharger whine

Stavros

Told you

Minis have PROPER Eaton superchargers, so whines like fuck.

Smaller pulley for more boost and the noise goes all WW2 fighter spec

AlexF

So come on steve - your right so far - now tell us where the wine comes from

big_wig_074

france?

Chip

iTrader: (3)

The whine comes from the rotor being very close together and acting like a musical instrument as they spin as far as im aware?

Stavros

I dont know, or really give much of a fuck, but proper chargers do it, gay centrifugal ones dont really, so its something proper ones do that belt driven turbo compressors dont.

Happens more the more load you put em under too, so more charger rpm or if you shut the throttle on one without a bypass.

So its summat to do with that, what exactly, i dunno.

Porkie

iTrader: (1)

Nasty noise... whiney, irritating and generally annoying. Much like Ima really!

Lambchop

iTrader: (1)

lol nice one

AlexF

Its UK wine isnt it


What drives BOTH screws?

What also makes a similar noise on rally cars (or minis )

Alex

big_wig_074

straight cut gears,but my first answer was better lol!

lead_foot

iTrader: (1)

Nothing sounds as good as a V8 with open exhaust mainfolds and a huge whining supercharger!!

lead_foot

iTrader: (1)

Yeah, what he said.

Stavros

Id heard it was the straight cut cogs too, but dont really believe it.

That dont make total sense to me as a lot of the noise is muffled by airboxes etc and gets tons louder with an induction kit etc.

Also centrifugal ones run straight cut cogs too but dont whine anywhere near as much, if at all, sound more like turbos.

So maybe thats some of the noise, but that dont make sense for some of it!

focusv8

My supercharger has Straight cut gears, which make it very noisey.

.

.

Stavros

What about my comments above your post, surely it cant account for all of the noise?

Chip

iTrader: (3)

Interesting stuff, if I spin the eaton ive got lieing about it sounds like its from the blades too, but obviously not then

As with stavros though, i dont care why, i just like the noise, lol

focusv8

Mines a Vortec straight cut Centrifugal,

They also do a superquiet Helical cut gear, the difference is very noticeable.

.

AlexF

Its probably a bit of both!

moving air is fucking noisy no matter how you do it!

Its DEFINATLY a cool noise

in fact I'm going to go make mine make it as often as possiblr for the next 40 mins

Alex

Chip

iTrader: (3)

drive home in first then

Porkie

iTrader: (1)

Apart from the SAME engine without the whine!!!!

GARETH T

i get the feeling your doing like the whine lee

Stavros

And V8s with open manifolds sound SHITE until they have high revs, like the shittest tractor on earth.

IMO

GARETH T

http://youtube.com/watch?v=EKUVaDDNH8w

thats how all V8's should sound

big_wig_074

i disagree gareth!
http://youtube.com/watch?v=DEn0I9LFbr8
THIS is what a v8 should be like!

GARETH T

doesnt sound as nice as the cs,,,

and that chassis needs some work

Charlie Chalk

iTrader: (1)

I love the Whine